The present invention relates to a manufacturing method of semiconductor devices by using a dry etching technology. More particularly, the present invention relates to a method of forming an interlayer insulating film of a dual trench metallization using an organic silicon film such as polysilane, a method of forming a contact hole and a trench, a method of forming a deep trench and a method of removing an anti-reflection film.
When a process for manufacturing semiconductor devices each having a multilayered metallization is performed, a step is frequently employed whereby the pattern of a contact hole or the like is formed on a multilayered insulating film constituted by, for example, a silicon oxide film, silicon nitride film and the like, such that a resist serves as a mask.
Hitherto, when a selective etching step of the silicon oxide film and the silicon nitride film is performed by using dry etching technology such as reactive ion etching (RIE), the selective ratio (the ratio of etching speeds) between the resist and the silicon nitride film can be raised. The selective etching can easily be performed. Since the etching selective ratio between the resist and the silicon nitride film cannot be raised, selective etching of the silicon nitride film using the resist as a mask cannot easily be performed.
In recent years, the integration of miniature trench capacitors at a high density has been required to manufacture large scale semiconductor memory devices. Therefore, formation of trenches each having a great depth compared to the size of the opening portion (hereinafter called a xe2x80x9chigh aspect ratioxe2x80x9d) on a semiconductor substrate by using the anisotropic dry etching is one of the important techniques.
When the trenches each having a high aspect ratio are formed on a semiconductor substrate, opening portions each having a high aspect ratio must be formed in an insulating film mask by using anisotropic dry etching. Hitherto, a resist mask has been employed to form the opening portions in the insulating film mask. To form opening portions each having a high aspect ratio, gas plasma excited by high power and high frequency radiation must be applied to the resist for a long time.
This leads to a fact that the opening portions in the resist are unevenly deformed. Therefore, a multiplicity of trenches each having a smooth inner surface and exhibiting satisfactory accuracy cannot easily be formed with a high yield in the semiconductor substrate.
As microfabrication technology progresses, the thickness of the resist must be reduced to raise the resolution of lithography. Since so-called film thinning occurs when the dry etching is performed, the trenches cannot easily be formed.
A common method of manufacturing semiconductor devices incorporates a smoothing process having the steps of forming isolation trenches for isolating devices from one another by using a silicon nitride film, the pattern of which has been formed on a semiconductor substrate as an etching mask, forming a thick silicon oxide film for isolating the devices from each other such that the isolation trenches are buried, and polishing the surface such that the silicon nitride film serves as a stopper (a suppression layer) so that the isolation trenches are buried with the oxide film and the device region is smoothed.
Where a multiplicity of silicon nitride film stoppers present in portions of high density device regions, the process for smoothing the device region using polishing of the surface enables satisfactory smoothing of the surface such that the isolation trenches are filled with the silicon oxide film. In the portions of low density device regions, the number of silicon nitride film stoppers is insufficiently small. Thus, the silicon oxide film is excessively polished in the smoothing process. As a result, there arises a problem in that smoothing and formation of the device regions cannot be performed uniformly over the overall surface of the wafer.
Therefore, a countermeasure is taken whereby a polysilicon film is deposited on the overall surface, and then a smoothing process is performed and the polysilicon film, as the etching mask, is left in the low density portion. The smoothing step, however, sometimes encounters a crack in the silicon oxide film in the low density portion. When the silicon nitride film stoppers on the device region and the polysilicon mask are removed, there arises a problem in that the silicon substrate is scooped out excessively.
Hitherto, a gate electrode has been formed by a method comprising the steps of forming a silicon nitride film on a metallic film for forming the gate electrode, forming a resist in a gate electrode formation region on the silicon nitride film, using the resist as a mask to form a nitride film, and using the silicon nitride film having a pattern formed after the resist mask has been separated to machine the metallic film as the gate electrode.
If the surface of the wafer has an uneven portion, the projecting portions of the surface of the wafer are excessively etched when the pattern of the silicon nitride film is formed. As a result, the metallic film formed below the pattern is undesirably etched, causing a problem to arise in that a gate electrode formation cannot be satisfactorily performed.
When an etching process is performed to form a self-aligned contact (hereinafter abbreviated as a xe2x80x9cSACxe2x80x9d), an opening of a contact hole is created in an interlayer insulating film for burying the space between the gate electrode. At this time, an edge line along which the upper surface and the side surface of the gate electrode intersect is exposed in the lower portion of the opening of the contact hole.
Undesirable etching of the gate electrode must be prevented during the etching process for opening the contact hole in the interlayer insulating film constituted by the silicon oxide film. Therefore, the gate electrode is usually coated with a silicon nitride film (an etching stopper) which has a high etching selective ratio with respect to the silicon oxide film. Although a satisfactory high etching selective ratio of the silicon nitride film with respect to the oxide film can be obtained in a flat portion, the etching selective ratio is lowered to about ⅓ or less of the flat portion in the edge line portion.
Therefore, the edge line portion of the gate electrode is undesirably etched when the contact hole is opened in the SAC formation step. Thus, the gate metal is exposed to the outside, causing a short-circuit fault to occur when the metallization metal is buried in the contact hole. As a result, it is known that the SAC cannot easily be formed in the process for manufacturing E2 PROM in which the gate electrode has a high aspect ratio (the ratio of the length of the gate and the height of the gate).
Since microfabrication technology has proceeded in recent years, etching of the interlayer insulating film at a high aspect ratio is frequently required. It is known that when dry etching of the silicon oxide film at a high aspect ratio is performed under the condition where a high etching selective ratio with respect to the silicon nitride film is permitted, residues such as fluorocarbon are left in the opening portion during the progress of the etching operation. Thus, etching is interrupted.
As a technology for forming a multilayered metallization, double-trench metallization (called a xe2x80x9cdual-damascene structurexe2x80x9d in this industrial field) is employed frequently. When fabrication of the interlayer insulating film having the dual-damascene structure is performed, miniaturized dry etching process technology is required which is a combination of trench formation for burying two layered metallizations and contact hole formation for connecting the two layered metallizations to each other.
Hitherto, it is very difficult to control the depth of the trenches in the surface of the wafer when the trenches are formed in the interlayer insulating film. To realize the control, a method has been employed with which a silicon nitride film is inserted into the interlayer insulating film constituted by the silicon oxide film, so that the silicon nitride film is used as the stopper for the dry etching. When the dual-damascene structure having a complicated shape is formed, the stopper constituted by the silicon nitride film is required to control the depth of the trench metallization of the upper layer after the contact hole has been formed.
In the foregoing case, the silicon nitride film, which has a dielectric constant higher than that of the silicon oxide film, is contained adjacent to the metallization. Therefore, the wiring capacitance is enlarged excessively, causing the operation speed of the semiconductor device to be reduced. When the trenches are formed, partial etching of the interlayer insulating film constituted by the silicon oxide film occurs. Thus, ions are concentrated in the bottom corners of each trench, causing a shape called xe2x80x9ctrenchingxe2x80x9d to be formed in the comers of each trench. Therefore, the wiring metal cannot be easily buried in the trench.
Hitherto, an LSI of a type having a mixed structure so that a DRAM (Dynamic Random Access Memory) and a logic are mounted on one chip is structured such that the alignment margin (a fringe) in the logic portion is about xc2xc of the opening portion of the alignment margin in the DRAM, owing to the difference in the design rule between the DRAM section and the logic section.
In an example case in which a contact hole is formed in an interlayer insulating film having the dual-damascene structure, the following step is employed: a dry etching condition where a high selectivity with respect to the etching stopper constituted by the silicon nitride film on the lower trench metallization is used to form the contact hole in the interlayer insulating film constituted by the silicon oxide film. Then, the silicon nitride film is removed, and then the wiring metal is buried in the contact hole and trenches of the upper metallization.
In the logic section, having a small alignment margin, a portion of the opening of the contact hole is sometimes deviated to the outside of the stopper constituted by the silicon nitride film which covers the lower trench metallization. Therefore, the interlayer insulating film constituted by the silicon oxide film which buries the side surface of the lower trench metallization easily encounters borderless etching that is cut during the step of forming the contact hole. Therefore, there arises a problem in that a fault in burring and a short-circuit fault of the wiring metal occur.
Hitherto, polysilane anti-reflective film is formed below the resist in the lithography step. When the resist is removed by performing O2 ashing after the pattern has been formed, a phenomenon undesirably occurs in that polysilane is oxidized. Thus, oxidized polysilane cannot easily be removed.
As described above, the conventional manufacturing method of semiconductor devices by using dry etching technology suffers from problems that etching at a high aspect ratio cannot easily be performed, smoothing of the overall surface of the wafer cannot easily be performed when the device region has some deviation in density of devices, the surface roughness causes defective fabrication when a miniaturized gate electrode is formed and short-circuit fault easily occurs in the edge line portion of the gate electrode when the SAC hole is formed.
Moreover, there arises a problem in that etching is interrupted owing to residues produced in the dry etching step when etching of an interlayer insulating film at a high aspect ratio is performed. Another problem arises in that a necessity for stacking a silicon nitride film to serve as an etching stopper to make the depths of the formed trenches uniform and to prevent borderless etching reduces the operation speed of the semiconductor device. In addition, trenching occurring when the trenches are formed causes a fault in burying of the wiring metal. Since the alignment margin in the logic section is too small, borderless etching easily occurs when a mixed memory logic LSI is manufactured. Another problem arises in that polysilane used to form the reflection preventing film for the resist cannot easily be removed. Thus, the conventional manufacturing method of semiconductor devices by using dry etching technology suffers from a multiplicity of problems.
To overcome the above-mentioned problems, an object of the present invention is to provide a method of forming a multilayered insulating film by using an organic polysilicon film made of, for example, polysilane, a removing method and a method of forming an etching mask.
The manufacturing method of semiconductor devices by using dry etching technology uses an organic silicon film made of, for example, polysilane, which is able to easily form a smooth surface by a coating process and which can easily be dry-etched and smoothed. The organic silicon film is laminated with an insulating film such as a silicon oxide film or a silicon nitride film, a metallic film for use in metallization or the like. Alternatively, the organic silicon film is formed on a semiconductor substrate such that the organic silicon film forms a portion of the foregoing element. While using the obtained structure as a suppression layer or the like for improving the processing shape of the insulating film portion, the organic silicon film is microfabricated. Thus, a portion comprising an interlayer insulating film having a complicated dual-damascene structure is formed. Then, for example, oxygen is introduced into the organic silicon film so as to change the organic silicon film into an insulating film constituted by an organic silicon film oxide film and the like. Thus, a required constituting element of a semiconductor device is provided.
For example, some of the organic silicon film, which has the silicon and silicon bonds as the main chain thereof, has anti-reflective property. The organic silicon film cannot be used, as it is, as an insulating film of a semiconductor device. When a step of introducing oxygen or the like is performed, such organic silicon film can be employed as the insulating film of the semiconductor device.
As described above, according to the present invention, control of the shape and the depth of the metallization trench, formation of a contact hole having a high aspect ratio, prevention of borderless etching and improvement of problems occurring in a smoothing step, which have been difficult for the conventional dry etching step, can be performed. Moreover, a new method of removing polysilane employed as an anti-reflective film is provided.
Specifically, a manufacturing method of semiconductor devices by using dry etching technology according to the present invention comprising the steps of: forming a organic silicon film on a semiconductor substrate, dry-etching the organic silicon film to form a portion that must be formed by the insulating film of the semiconductor device by using the organic silicon film, and changing the organic silicon film into an insulating film so that the portion of the semiconductor device constituted by the insulating film is formed.
It is preferable that the organic silicon film has silicon and silicon bonding as a main chain thereof
It is preferable that the method of manufacturing semiconductor devices has a structure that at least any one of oxygen, nitrogen, hydrogen and carbon elements is introduced into the organic silicon film following dry etching of the organic silicon film so that the organic silicon film is changed to any one of organic silicon oxide film, an inorganic silicon oxide film, a silicon oxide film and a silicon nitride film.
It is preferable that the step of introducing at least any one of oxygen, nitrogen, hydrogen and carbon elements into the organic silicon film is performed by using any one of a RIE method, an ashing method and an ion implanting method using ions of the elements or a mixture of the elements.
It is preferable that the step of introducing at least any one of oxygen, nitrogen, hydrogen and carbon elements into the organic silicon film is performed by performing heat treatment in a gas atmosphere composed of the element or a mixture of the elements.
It is preferable that the portion constituted by the insulating film of the semiconductor device is formed by at least any one of an interlayer insulating film between the surface of the semiconductor substrate and a lower metallization layer of a dual-damascene structure, an insulating film for burying the space between wiring metals formed in each metallization layer of the dual-damascene structure and an interlayer insulating film between upper and lower metallization layers of the dual-damascene structure.
It is preferable that the organic silicon film is laminated on the insulating film and the dry etching of the organic silicon film is performed such that the insulating film is employed as a suppression layer of the dry etching.
It is preferable that the portion constituted by the insulating film of the semiconductor device is formed by an interlayer insulating film including a contact hole of the dual-damascene structure formed on the semiconductor substrate and a trench in each of the upper and lower metallization layers of the dual-damascene structure.
It is preferable that the step of forming the contact hole incorporates the steps of: coating the overall upper surface of the lower metallization layer with the organic silicon film; providing the contact hole which reaches the upper surface of the wiring metal in the lower metallization layer for the organic silicon film by selectively dry-etching the organic silicon film; and changing the organic silicon film in which the contact hole has been formed into any one of an organic silicon oxide film, an inorganic silicon oxide film, a silicon oxide film, and a silicon nitride film.
It is preferable that the lower metallization layer is constituted by a trench metallization buried in the insulating film of the semiconductor substrate, and the upper surface of the insulating film suppresses borderless etching when the contact hole is formed.
It is preferable that the step of forming the trench includes the steps of: coating the overall upper surface of the insulating film on the semiconductor substrate with the organic silicon film; removing the portion of the organic silicon film in which the trench has been formed by selectively dry-etching the organic silicon film; and changing the organic silicon film subjected to the removal step into an insulating film constituted by any one of an organic silicon oxide film, an inorganic silicon oxide film, a silicon oxide film and a silicon nitride film.
It is preferable that the step of forming the interlayer insulating film includes the steps of: forming the contact hole in the insulating film on the semiconductor substrate; coating the overall surface of the insulating film with the organic silicon film such that the contact hole is buried; removing a portion of the upper metallization layer including an opening portion of the contact hole in which the trench has been formed and the organic silicon film in the contact hole by selectively dry-etching the organic silicon film; and changing the organic silicon film subjected to the removal step into an insulating film constituted by any one of an organic silicon oxide film, an inorganic silicon oxide film, a silicon oxide film and a silicon nitride film.
It is preferable that the manufacturing method of semiconductor devices has a structure that the step of removing the organic silicon film is performed such that the upper surface of the insulating film on the semiconductor substrate controls the dry etching so that the organic silicon film is selectively etched.
It is preferable that the step of forming the interlayer insulating film includes a step of coating the overall upper surface of a first insulating film on the semiconductor substrate on which the lower metallization layer has been formed with the organic silicon film, a first selective dry etching step of forming a contact hole which reaches the upper surface of the metallization of the lower metallization layer, a step of changing the organic silicon film having the contact hole into a second insulating film constituted by any one of an organic silicon oxide film, an inorganic silicon oxide film, a silicon oxide film and a silicon nitride film, a step of coating the overall upper surface of the second insulating film with the organic silicon film, a second selective dry etching step of forming a trench in the upper metallization layer connected to the contact hole formed on the second insulating film by removing the organic silicon film in the portion of the upper metallization layer including the opening portion of the contact hole on which the trench has been formed and the inside portion of the contact hole, and a step of changing the organic silicon film having the trench in the upper metallization layer into a third insulating film constituted by any one of an organic silicon oxide film, an inorganic silicon oxide film, a silicon oxide film and a silicon nitride film.
It is preferable that the manufacturing method of semiconductor devices has a structure that the first insulating film suppresses borderless etching occurring in the periphery of the lower metallization layer in the first dry etching step, and the second insulating film controls the second selective dry etching step of forming the trench in the upper metallization layer.
It is preferable that the step of forming the interlayer insulating film includes the steps of: forming any one of a first organic silicon oxide film, an inorganic silicon oxide film and a silicon oxide film on the insulating film on the semiconductor substrate on which the lower metallization layer has been formed; forming a stopper for dry etching constituted by an organic silicon film on any one of the first organic silicon oxide film, the inorganic silicon oxide film or the silicon oxide film; providing an opening portion for forming the contact hole which reaches the lower metallization layer for the stopper; forming any one of a second organic silicon oxide film, an inorganic silicon oxide film or a silicon oxide film such that the stopper having the opening portion is buried; forming an etching mask for forming a trench of the metallization layer to correspond to the opening portion; and continuously and selectively dry-etching any one of the first and second organic silicon oxide film, the incorporate silicon oxide film or the silicon oxide film by using the etching mask and the stopper having the opening portion.
It is preferable that a step is included in which the stopper for dry etching constituted by the organic silicon film is subjected to the step of continuously and selectively dry-etching the first and second organic silicon oxide film, the inorganic silicon oxide film or the silicon oxide film and changed into an organic silicon oxide film so as to be integrated as a portion of the interlayer insulating film.
The manufacturing method of semiconductor devices by using dry etching technology according to the present invention comprises the steps of: forming an organic silicon film having bondings of silicon and silicon as the main chains thereof on a semiconductor substrate and selectively introducing any one of oxygen, nitrogen, hydrogen and carbon elements into at least the surface of the organic silicon film; forming a portion of the semiconductor device constituted by insulating material by performing selective dry etching such that the surface of the organic silicon film is used as a mask; and introducing at least any one of oxygen, nitrogen, hydrogen and carbon elements into the organic silicon film after the organic silicon film has been dry-etched to integrate both of the surface of the organic silicon film and the inside portion of the organic silicon film as any one of an organic silicon oxide film, an inorganic silicon oxide film, a silicon oxide film and a silicon nitride film.
It is preferable that the manufacturing method of semiconductor devices is structured to perform selective dry etching such that the surface of the organic silicon film is used as a mask to process the edge in the periphery of the opening portion of the mask to be rounded.
The manufacturing method of semiconductor devices by using dry etching technology according to the present invention comprises the steps of: forming an organic silicon film having bondings of silicon and silicon as the main chains thereof on a semiconductor substrate and selectively introducing any one of oxygen, nitrogen, hydrogen and carbon elements into at least the surface of the organic silicon film; forming a portion of the semiconductor device constituted by insulating material by performing selective dry etching such that the surface of the organic silicon film is used as a mask; introducing at least any one of oxygen, nitrogen, hydrogen and carbon elements into the organic silicon film after the organic silicon film has been dry-etched to make the surface of the organic silicon film and the inside portion of the organic silicon film to be constituted by different type films which are an organic silicon oxide film, an inorganic silicon oxide film, a silicon oxide film and a silicon nitride film; and removing the mask by performing selective etching of the surface of the organic silicon film and the inside portion of the organic silicon film.
The manufacturing method of semiconductor devices by using dry etching technology according to the present invention comprises the steps of: using an organic silicon film to form an anti-reflective film for use in a photolithography step on the upper surface of the insulating film on a semiconductor substrate, introducing any one of oxygen, nitrogen, hydrogen and carbon elements into the organic silicon film after the photolithography step has been completed to constitute the anti-reflective film by any one of an organic silicon oxide film, an inorganic silicon oxide film, a silicon oxide film and a silicon nitride film; and integrating the anti-reflective film with the insulating film.
The manufacturing method of semiconductor devices by using dry etching technology according to the present invention comprises the steps of: using an organic silicon film to form an anti-reflective film for use in a photolithography step on the upper surface of the insulating film on a semiconductor substrate; introducing any one of oxygen, nitrogen, hydrogen and carbon elements into the organic silicon film after the photolithography step has been completed to constitute the anti-reflective film by any one of an organic silicon oxide film, an inorganic silicon oxide film, a silicon oxide film and a silicon nitride film; and removing the anti-reflective film by etching by using selective etching of the anti-reflective film and the insulating film subjected to the process.
A manufacturing method of semiconductor devices by using dry etching technology according to the present invention comprises the steps of: forming a thermal oxide film on a semiconductor substrate; forming a silicon oxide film on the organic silicon film by coating the thermal oxide film with an organic silicon film; forming an opening portion which reaches the surface of the semiconductor substrate on a multilayered film constituted by the silicon oxide film and the organic silicon film; changing the organic silicon film to a silicon nitride film by introducing nitrogen into the organic silicon film subjected to the step; and forming a trench on the semiconductor substrate by using a multilayered film constituted by the silicon oxide film and the silicon nitride film as a mask.
A manufacturing method of semiconductor devices by using dry etching technology according to the present invention comprises the steps of: coating a semiconductor substrate with an organic silicon film to form the pattern of the organic silicon film by using a resist as a mask such that a device region on the semiconductor substrate is covered; and forming an isolation trench in the semiconductor substrate by using the organic silicon film, the pattern of which has been formed, and the resist as masks and changing the organic silicon film to a silicon nitride film by introducing nitrogen into the organic silicon film.
It is preferable that the manufacturing method of semiconductor devices comprises the steps of: furthermore coating the overall upper surface of the semiconductor substrate, on which the isolation trench has been formed, with the organic silicon film such that the isolation trench is buried; smoothing the surface of the organic silicon film by using the semiconductor as a suppression layer; and changing the organic silicon film into any one of a silicon oxide film, an organic silicon oxide film and an inorganic silicon oxide film by introducing oxygen into the organic silicon film with which the isolation trench is buried.
A manufacturing method of semiconductor devices by using dry etching technology according to the present invention comprises the steps of: forming a gate insulating film on a semiconductor substrate and forming at least one metallic film on the gate insulating film; forming the pattern of the organic silicon film in a region of the semiconductor substrate which has been covered with the mask and in which the gate electrode has been formed such that a resist is used as a mask; forming the pattern of a gate electrode constituted by the metallic film in the region in which the gate electrode has been formed such that the organic silicon film, the pattern of which has been formed, and the resist are used as masks; and changing the organic silicon film, the pattern of which has been formed, into a nitride film by introducing nitrogen into the organic silicon film.
A manufacturing method of semiconductor devices by using dry etching technology according to the present invention comprises the steps of: forming a gate insulating film on a semiconductor substrate, forming at least one metallic film on the gate electrode insulating film and forming the pattern of a gate electrode constituted by the metallic film on a region of the semiconductor substrate which is covered with the metallic film and in which a gate electrode will be formed; covering the gate electrode with a silicon nitride film and depositing a first insulating film on the overall upper surface of the semiconductor substrate such that the gate electrode is buried; smoothing the surface of the first insulating film and coating the surface of the smoothed first insulating film with an organic silicon film; forming a contact hole which reaches the first insulating film in the organic silicon film by selectively removing the organic silicon film that covers adjacent to the gate electrode where either of a source or a drain will be formed and a portion of the gate electrode adjacent to the source or the drain by performing dry etching using a resist as a mask; a step of exposing the silicon nitride film to the bottom portion of the contact hole by dry-etching the first insulating film by using the resist and the organic silicon film as masks; in a self-aligning manner, exposing the surface of either of region on the surface of the semiconductor substrate in which the source will be formed or a region in which the drain will be formed; and integrating the organic silicon film with the first insulating film and using the contact hole to connect metallizations by changing the organic silicon film into a second insulating film constituted by any one of an organic silicon oxide film, an inorganic silicon oxide film, a silicon oxide film and a silicon nitride film.
A manufacturing method of semiconductor devices by using dry etching technology according to the present invention comprises the steps of: forming a gate insulating film on a semiconductor substrate, forming at least one metallic film on the gate insulating film and forming the pattern of a gate electrode constituted by the metallic film in a region of the semiconductor substrate that is covered with the metallic film and in which the gate electrode will be formed; furthermore covering the first silicon oxide film by covering the gate electrode with a silicon nitride film and depositing the gate electrode on the silicon nitride film; forming a contact hole which reaches the first silicon oxide film in the organic silicon film by coating the overall upper surface of the semiconductor substrate with the organic silicon film and by selectively removing the organic silicon film that covers a region adjacent to the gate electrode in which a source or a drain will be formed and a portion of the gate electrode adjacent to the portion in which the source or the drain will be formed by performing dry etching which uses a resist as a mask; removing the first silicon oxide film exposed to the bottom surface of the contact hole by introducing oxygen into the organic silicon film to change the organic silicon film into a second silicon oxide film and by performing dry etching such that the second silicon oxide film is used as a mask; and in a self-alignment manner, exposing the surface of the region that has been formed on the semiconductor substrate and in which the source or the drain will be formed and using the contact hole for connecting metallizations by further removing the silicon nitride film and gate insulating film exposed owing to removal of the first silicon oxide film.
A dry etching method according to the present invention comprises: a step of forming an organic silicon film having main chains thereof constituted by bondings of silicon and silicon on a semiconductor substrate and forming a portion of the semiconductor device constituted by insulating material dry-etching at least the organic silicon film; and a step of changing a portion of the organic silicon film into an insulating film constituted by any one of an organic silicon oxide film, an inorganic silicon oxide film, a silicon oxide film and a silicon nitride film by processing the processed organic silicon film by executing at least heat treatment which is performed in O2, N2 or H2 gas, heat treatment which is performed in O2, N2 or H2 plasma, or implantation of O2, N2 or H2 ions and heat treatment.
Additional objects and advantages of the invention will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.